Google has added another family member to its autonomous vehicle program, and an eagle-eyed reader in Southern California caught the Big G's Lexus RX450h out and about during testing.

From what we can gather from the image, Google has refined the design of its top-mounted array of sensors, culling things down into a more compact package that's both smaller and more aerodynamic than those found on its fleet of Toyota Prius hybrid vehicles.

Google began testing its autonomous vehicle program over two years ago under the supervision of Dr. Sebastian Thrun, the director of the Stanford Artificial Intelligence Laboratory and a Google engineer who co-invented the Street View mapping service.

Initially, Google ran the program in stealth mode, using six Prius hybrids and one modified Audi TT, later pulling the covers off its skunkworks project in late 2010.

A Google spokesperson tells Wired, "In the course of our work, we experiment with testing our algorithms on various vehicles to help us improve our technology," and confirmed that the Lexus crossover is part of Google's expanded fleet.